To count the days in the notice period:
The first day is the day after the notice is served.
Then count every day on the calendar, including weekends and holidays.
If the last day of the notice period falls on a holiday or weekend, then the notice period ends the next work day.
The information presented here is general in nature and is not intended, nor should be construed, as legal advice. This posting does not create any attorney-client relationship with the author (who is only admitted to practice law in the State of California). For specific advice about your particular situation, consult your own attorney.
The first day would be the day after you are served with a 3 day notice. A 3 day notice can be served by posting and mailing, it does not need to be personally served. Look on the notice to see what days are listed as days the landlord will accept payment. Even if the last day falls on a weekend or holiday, it will count if the landlord is able to accept payment. If payment is by mail only, then obviously the last day cannot fall on a Sunday or holiday.